code: def target_atom(self) -> Optional[str]:
      # target_atom: "{" ~ target_atoms? "}" | "[" ~ target_atoms? "]" | NAME "*" | NAME | NUMBER | STRING | "?" | ":" | !"}" !"]" OP
      mark = self._mark()
      cut = False
      if (
          (literal := self.expect("{"))
          and (cut := True)
          and (atoms := self.target_atoms(),)
          and (literal_1 := self.expect("}"))
      ):
          return "{" + (atoms or "") + "}"
      self._reset(mark)
      if cut:
          return None
      cut = False
      if (
          (literal := self.expect("["))
          and (cut := True)
          and (atoms := self.target_atoms(),)
          and (literal_1 := self.expect("]"))
      ):
          return "[" + (atoms or "") + "]"
      self._reset(mark)
      if cut:
          return None
      if (name := self.name()) and (literal := self.expect("*")):
          return name.string + "*"
      self._reset(mark)
      if name := self.name():
          return name.string
      self._reset(mark)
      if number := self.number():
          return number.string
      self._reset(mark)
      if string := self.string():
          return string.string
      self._reset(mark)
      if literal := self.expect("?"):
          return "?"
      self._reset(mark)
      if literal := self.expect(":"):
          return ":"
      self._reset(mark)
      if (
          self.negative_lookahead(self.expect, "}")
          and self.negative_lookahead(self.expect, "]")
          and (op := self.op())
      ):
          return op.string
      self._reset(mark)
      return None
  
imports: import ast
  import sys
  import tokenize
  from typing import Any, Optional
  from pegen.parser import memoize, memoize_left_rec, logger, Parser
  from ast import literal_eval
  from pegen.grammar import Alt, Cut, Forced, Gather, Group, Item, Lookahead, LookaheadOrCut, MetaTuple, MetaList, NameLeaf, NamedItem, NamedItemList, NegativeLookahead, Opt, Plain, PositiveLookahead, Repeat0, Repeat1, Rhs, Rule, RuleList, RuleName, Grammar, StringLeaf
label_desc: Use image node_id 21 for calling the GeneratedParser obj's underlying member method code with example usage: obj.target_atom() and returns: None, unknown, None, unknown, None, unknown, name, number, string, str, str, op